Understanding the Types of Sample Tubes in Laboratories

In laboratory settings, the collection and preservation of samples are crucial for accurate test results. One of the most essential tools in this process is the sample tube. Sample tubes come in various types, each designed for specific purposes and containing particular additives that facilitate different testing methodologies. Here, we will explore the most common types of sample tubes used in laboratories, along with their specific applications.

1. EDTA Tubes (Purple Top) EDTA (Ethylenediaminetetraacetic acid) tubes are primarily used for hematology tests. The EDTA acts as an anticoagulant, preventing blood from clotting and allowing for the accurate measurement of blood components such as red blood cells, white blood cells, and platelets. These tubes are essential for complete blood counts (CBC) and blood smears.

3. Gel Separator Tubes (Gold or Red/Gray Top) These tubes contain a gel that separates serum from blood components upon centrifugation. The gel forms a barrier between serum and cells, allowing for easier extraction of the serum for various biochemical analyses. These tubes are often used for routine chemistry tests due to their convenience and efficiency in sample processing.

4. SST Tubes (Serum Separator Tubes, Gold Top) SST tubes are similar to gel separator tubes but may contain clot activators to speed up the clotting process. They are ideal for obtaining serum samples for serology and biochemical assays, making them a popular choice in clinical laboratories.

5. Heparin Tubes (Green Top) Heparin tubes are used for tests requiring plasma. They contain heparin as an anticoagulant, which inhibits thrombin and prevents clotting. These tubes are commonly used in chemistry panels and for plasma-based assays.

6. Gray Top Tubes These tubes contain sodium fluoride and potassium oxalate, making them suitable for glucose testing. Sodium fluoride acts as a glycolysis inhibitor, preserving glucose levels in the sample for accurate analysis.

In summary, the choice of sample tube is critical in laboratory testing, as each type has specific uses based on the properties of the additive it contains. Proper understanding and use of these tubes enhance the reliability of test results, ultimately supporting accurate diagnoses and patient care. Labs must adhere to the correct protocols for tube selection to ensure the integrity and accuracy of samples throughout the testing process.